Sealing of a thermal turbomachine

ABSTRACT

The invention relates to a honeycomb structure ( 1 ) which is arranged on a stator of a gas turbine and which is arranged opposite the moving blades of the gas turbine. The honeycomb structure ( 1 ) is composed of metal sheets ( 5 ) in such a way that webs ( 3 ) having double the sheet thickness are obtained and connections ( 4 ) of single thickness are obtained between the webs ( 3 ). The angle (α) between the circumferential direction ( 2 ) of the stator and the webs ( 3 ) of double thickness is 5° to 175°. This serves to avoid undesirable effects such as, for example, overheating during friction at the honeycomb structure ( 1 ) of the moving blades of the gas turbine.

[0001] The invention deals with the sealing of a thermal turbomachine according to the preamble of claim 1.

[0002] The guide and moving blades of gas turbines are subjected to high loads. In order to keep down the leakage losses of the gas turbine, the moving blade of the gas turbine is fitted relative to the stator in such a way that grazing occurs. A honeycomb structure is attached to the stator of the gas turbine in a position opposite the moving blade. The moving blades work themselves into this structure, so that a minimum sealing gap occurs between the moving blades and the honeycomb structure. The honeycomb structure consists of a heat-resistant metal alloy. It is composed of a plurality of sheet-metal strips which are bent in accordance with the subsequent shape. This construction of the honeycombs results in double-walled webs and connections of single thickness between the webs.

[0003] It is known from the prior art to arrange the double-walled webs of the honeycomb structure in the circumferential direction of the stator. However, this does not have very advantageous effects on the frictional behavior of the moving blades. Thus excessive heating may occur if the blade tip covers a plurality of honeycombs and therefore rubs continuously on the double configurations.

[0004] The aim of the invention is to overcome these disadvantages. The invention achieves the object of improving the frictional behavior between the moving blades and the honeycomb structure and of reducing the undesirable secondary effects of the friction, such as, for example, heating of the components involved.

[0005] According to the invention, the aim is achieved in a honeycomb structure according to the preamble of claim 1 in that the angle between the circumferential direction of the stator and the webs of double thickness is 5° to 175°.

[0006] In order to achieve the same aim, the sheet thickness of the individual sheets at the points at which the sheets on the honeycomb structure form the webs may advantageously be reduced relative to the sheet thickness of the connections.

[0007] In a further embodiment, the length of the webs may be reduced in relation to the length of the connections, so that a deformed honeycomb is obtained. The ratio of the length of the webs to the length of the connections between the webs of the deformed honeycomb may be 1:1 to at most 1:20. The effect can additionally be assisted if the angle between a web and the two adjacent connections varies between 60° and 120°.

[0008] The invention is explained with reference to the attached drawings, in which:

[0009]FIG. 1 shows a first embodiment of an arrangement according to the invention of a honeycomb structure, and

[0010]FIG. 2 shows a second embodiment of a honeycomb structure according to the invention.

[0011] Only the elements essential for the invention are shown. The same elements are provided with the same reference numerals in different figures.

[0012] The invention relates to a sealing system between the moving blades and the stator of a gas turbine. A honeycomb structure 1 in FIG. 1, which is fastened to the stator (not shown), consists of individual metal sheets 5 of a heat-resistant alloy. The sheets 5 are formed in such a way that they form hexagonal honeycombs. In this case, the sheets 5 are fastened to one another at webs 3, so that the structure 1 is of double-walled design at these points. There are connections 4 of single thickness between the webs 3.

[0013] According to the invention, the honeycomb structure 1 is attached to the stator in such a way that there is an angle α of 5° to 175° between the axis which forms the webs 3 and a circumferential direction 2 of the stator or the moving blades of the gas turbine.

[0014] The frictional behavior of the moving blades at the honeycomb structure 1 can be improved by this arrangement, since, in particular, overheating of the affected parts is limited by avoiding permanent friction at the double-walled webs 3.

[0015] In a further embodiment, the sheet thickness of the individual sheets 5 at the points at which the sheets 5 on the honeycomb structure 1 form the webs 3 may be reduced relative to the sheet thickness of the connections 4. This also improves the frictional behavior between the moving blades and the honeycomb structure 1.

[0016] In a second embodiment, which likewise improves the frictional behavior and is shown in FIG. 2, the honeycomb is “deformed”. In this case, the length b of the webs 3 with respect to the length a of the connections 4 may be in a ratio of 1:1 to at most 1:20. The effect may additionally be assisted if the angle β between a web 3 and the two adjacent connections 4 varies between 60° and 120°. 

1. A honeycomb structure (1) which is arranged on a stator of a thermal turbomachine and which is arranged opposite the moving blades of the thermal turbomachine, the honeycomb structure (1) being composed of metal sheets (5) in such a way that webs (3) having double the sheet thickness are obtained and connections (4) of single thickness are obtained between the webs (3), characterized in that the angle (α) between the circumferential direction (2) of the stator and the webs (3) of double thickness is 5° to 175°.
 2. The honeycomb structure (1) as claimed in claim 1, characterized in that the sheet thickness of the individual sheets (5) at the points at which the sheets (5) on the honeycomb structure (1) form the webs (3) is reduced relative to the sheet thickness of the connections (4).
 3. The honeycomb structure (1) as claimed in claim 1, characterized in that the ratio of the length (b) of the webs (3) to the length (a) of the connections (4) between the webs (3) of the honeycomb is 1:1 to 1:20.
 4. The honeycomb structure (1) as claimed in one of claims 1 to 3, characterized in that the angle (β) between a web (3) and the two adjacent connections (4) is between 60° and 120°.
 5. The honeycomb structure (1) as claimed in one of claims 1 to 4, characterized in that the thermal turbomachine is a gas turbine. 